It is known that carbon-carbon double bonds in polymers may be hydrogenated by treating the polymer with hydrogen in the presence of a catalyst. Such processes can be selective in the double bonds which are hydrogenated so that, for example, the double bonds in aromatic or naphthenic groups are not hydrogenated and double or triple bonds between carbon and other atoms such as nitrogen or oxygen are not affected. This art field contains many examples of catalysts suitable for such hydrogenations, including catalysts based on cobalt, nickel, rhodium and ruthenium. The suitability of the catalyst depends on the extent of hydrogenation required, the rate of the hydrogenation reaction and the presence or absence of other groups, such as carboxyl and nitrile groups, in the polymer. Another factor to be considered is the cost, availability and quantity required of the catalyst.
U.S. Pat. No. 3,454,644 teaches the hydrogenation of unsaturated organic compounds having from 2 to 20 carbon atoms which organic compounds contain at least one moiety selected from keto, formyl, nitrile, nonaromatic carbon double bonds and carbon-carbon triple bonds, by using as the catalyst a metal complex of ruthenium or osmium bonded to two electro negative species selected from hydrogen and halogen and complexed with at least two organic stabilizing ligands such as carbonyl or tertiary phosphine.
A. Andriollo et al in J.A.C.S. 1989 Volume 111 pages 7431-7437 describe the use of the osmium complexes OsHCl(CO)(PR.sub.3).sub.2, where PR.sub.3 is P-(isopropyl).sub.3 or P methyl(tertiarybutyl).sub.2, for the catalytic sequential hydrogenation of phenylacetylene. M. A. Esteruelas et al in J. Molecular Catalysis 1989 Vol. 53 pages 43-52 describe the reduction of unsaturated ketones catalyzed by OsHCl(CO)(PR.sub.3).sub.2 where R is isopropyl.
The present invention is directed to a process wherein the rate of hydrogenation is high, the hydrogenation reaction is not affected by the presence or absence in the polymer of other groups such as aromatic, naphthenic, carboxyl or nitrile groups and the extent of hydrogenation is high.